The present invention relates to the field of surgical instruments and particularly to surgical clamps.
Major resections of the liver require divisions of large veins and thick vascular tissue. It is not always possible to ligate these structures prior to cutting them, and uncontrollable intra-operative bleeding is a major complication. Occlusion clamps, which can isolate the portion of the liver to be resected, provide major improvements in the success and speed of these operations.
U.S. Pat. No. 4,286,361 to MacKenzie; U.S. Pat. No. 3,747,172 to Tarzian; and U.S. Pat. No. 4,521,940 to Oetiker teach hose clamps. U.S. Pat. No. 3,840,018 to Heifetz and U.S. Pat. No. 4,821,720 to Hajduch teach clamps for medical tubing. These clamps are all intended for clamping tubular structures. Such clamping is accomplished through a single band, which is formed into a circle, and tightened to clamp the tubular structure. None of these clamps are applicable to clamping organs such as the liver, which are not tubular in structure.
Doty et al. in U.S. Pat. No. 3,667,471 teaches a liver clamp comprising a rigid elongated base member supporting two flexible foam rubber covered blades and a means for independent adjustment of each blade. A handle is attached to one end of the clamp base. There are several limitations in this design. The construction is complex, consisting of multiple moving parts requiring sophisticated machining. The clamp requires multiple steps to use in that the inferior and superior blades must be prepositioned and then the superior blade tightened and the interior blade compressed in order to use the clamp. The rigid base, in addition to the movable blades, makes the clamp more cumbersome. Also the blade is not readily adaptable to different size livers, because of the fixed length of the inferior blade. The clamp will not evenly compress the entire line of resection, but will compress the center more than the ends, because of the fixed length of the inferior and superior blades between the two points where they meet. This uneven compression often results in bleeding at the ends of the liver, where there is the least compression.
The Longmire-Storm clamp (V. Mueller, Stainliss, Germany, catalogue # SU-9080) is one of the earliest devices used in liver resection. Like the Doty clamp, it comprises flexible upper and lower bands of fixed length which are attached at both ends. However, because of its fixed size, it is not usable with all livers, and like the Doty clamp, it does not evenly compress the entire line of resection on those livers where it is usable, resulting in bleeding at the ends of the liver.
Accordingly, a need exists for a surgical clamp adaptable to different sized organs, capable of applying evenly distributed pressure.